Electric hammer.



PATENTED DEC. 20, 1904.

W. F. WAGNER. ELECTRIC HAMMER.

APPLICATION FILED JULY 11, 1904.

N0 MODEL.

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WVILLIAM F. WVAGNER, OF NEVv YORK, N. Y.

ELECTRIC HAMMER.

SPECIFICATION forming part of Letters Patent No. 778,206, dated December20, 1904. Application filed July 11, 1904. erial No. 216,099.

To (LZZ whom it natty concern:

Be it known that I, IVILLIAM F. AGNER, a

citizen of the United States, and a resident of the borough ofManhattan, in the city and State of New York, have invented a new anduseful Electric Hammer, of which the following is a specification.

My invention relates to electric hammers, with the object in view ofproviding an efficient machine of this character for general use.

In the accompanying drawings, Figure 1 is a view of the machine inlongitudinal section; and Fig. 2 is a diagrammatical view of the same,showing the connections of the electric conductors.

The machine consists of a central tube 1, preferably of brass,surrounded bya plurality of coils, in the present instance four;(denoted by 2, 3, 4, and 5, respectively.) The coils 2, 3, and 4 arewound in one direction, and the coil 5, which I term thedemagnetizing-coil, in the reverse direction. The coil 2 is separatedfrom the coil 3 at its end by interposed washers 6 7, the coil 3 fromthe coil 4 by interposed washers 8 9, and the coil 4 from the coil 5 byinterposed washers 10 11.

Theseveral coils are covered by an exterior casing 12, preferably ofsteel, which, by means of an internal shoulder 13, holds the chuck 14 inposition with its shank 15 within the central tube 1, while the exteriorcasing 12 is itself held in position by a couplingsleeve 16. Thecoupling-sleeve 16 has an .internal shoulder 17, which engages anexternal shoulder 18 on the casing 12, while a screwthread 19 on theinterior of the coupling sleeve engages an exterior screw-thread 20 onthe shank 21 of the handle 22. The inner end of the shank 21 pressesagainst a washer 23 at the end of the coil 2, thus serving to hold theseveral coils crowded together end to end between the chuck and handle.A conduit 24 in the handle and its shank connects the interior space 25of the hollow handle with an annular recess 26 on the shank for thepassage of the wires which connect the coils with the commutator andsource of electric energy, and it is intended that the wires leading tothe several coils shall pass along exterior tube 1 as the hammer to thecoils, between them and the interior of the casing 12, to the annularrecess 26 and along it to the conduit 24. A switch 27, located withinthe front portion of the handle, may be operated by a s pring-actuatedplunger 28, so mounted in the handle as to bring it within convenientreach of the thumb of the operator when the hand grasps the handle.

A head-block 29 has a screw-threaded engagement with the interior of theshank 21 and has attached to its inner face a cushionspring 30. Theblock 29 and spring 30 may be removed at pleasure by unscrewing theblock 29, a hole 31 angular in cross-section being provided in the blockfor that purpose. The hole 31 also serves to admit air to and permit itsescape from the interior of the reciprocates. The block 29 also servesto hold thetube 1 snugly between it and the chuck.

l/Vithin the tube 1 a hammer 32, subject to become magnetized by acurrent of electricity through the coils, after the manner of thewell-known solenoid, reciprocates between the spring-cushion 30 and theshank 33 of the tool 34, inserted in the chuck. Air is permitted toescape freely from in front of the hammer as it advances toward theshank of the tool by air-passages 35 extending along within the wall oftho chuck-shank and thence outwardly through the casing 12.

The manner of connecting the wires with the several coils, commutator,and electric generator is clearly shown in Fig. 2, in which the electricgenerator is denoted conventionally at 36 and the commutator at 37. Thebrush 38 of the commutator is assumed to rotate on an axis 39 to makeelectric contact with the several segments, in the present instancefour, of the commutator, and these segments (denoted by 40,41, 42, and43) are so constructed that the time of transit across the segment 40will be materially less than across the subsequent segments for reasonswhich will appear later on.

ator 36 is connected by a wire 44 with the inner ends of the coils 2, 3,4, and 5, as follows: The wire 44 leads to one binding-post of theswitch 27, and from the other bindingpost of said switch a wire 45 leadsto the inner One pole of the generend of the coil 2, while branch wires46 and 7 lead from the wire 45 to the inner ends of the coils 3 and 4,respectively, and a wire 48 connects the outer end of the coil 3 withthe inner end of the coil 5. The other pole of the generator 36 isconnected by a wire 49 with the brush 38 on the commutator. A wire 50connects the segment 40 ot the commutator with the outer end of the coil5 and a branch wire 51 also connects the outer end of the coil 5 withthe segment 42 of the commutator. The segment 41 ot the commutator isconnected by a wire 53 with the outer endof the coil 4, and a wire 54connects the segment 43 of the commutator with the outer end of the coil2.

Assuming the brush 38 to be in the position shown in Fig. 2 and to betraveling in the direction indicated by the arrow, the hammer 32 willhave been withdrawn from the tool by the energizing of the coil 3 andthe simultaneous demagnetizing of the tool-shank 33 by the reversecurrent in the coil 5, which current is established whenever the coil 3is energized, because of the connections 48 and 50, hereinaboveexplained. As the brush 38 leaves the segment 42, which should takeplace just before the hammer reaches the midway position with respect tothe coil 3, the coil 2 will become energized through the segment 43 andits con; nections and the hammer will be drawn outwardly against thespring-cushion 30. The return action of the cushion 30 is made tocorrespond as nearly as may be with the passing of the brush 38 from.the segment 43 onto the segment 40, and the consequent energizing of thecoil 3. The stroke of thehammer toward the tool is further powerfullyaugmented by the passing of the brush 38 from the segment 40 onto thesegment 41, which energizes the coil 4, while at the same time itdeeuergizes the coil 3, thereby removing any retarding influence. Thesaid augmenting of the stroke is produced by making the coil 4 of higherinductive power than the coils 3 and 2, in the present instance byincreasing the number of turns or convolutions of the wire whichcomposes it, so that as the hammer in its movement toward the tool comeswithin the influence of the coil 3 it will be drawn with increased powertoward the tool up to the instant of impact. Just as soon as the impactof the hammer on the tool has taken place the brush 38 has passed ontothe segment 42, and the coil 3 has become energized at the same timewith the demagnetizing effect of the coil 5 and the hammer starts on itsreturn movement. The segment 40 is of less breadth than the othersegments, and the time required for the brush to traverse it istherefore less, so that the advance stroke of the hammer is not retardedby the influence of the coil 3, while the return stroke because of thebreadth of the segment 42 may be retarded and the pounding against thehand of the operator thereby materially modified. The position of theend of the tool-shank with respect to the coil 4 and the hammer is suchthat it from any cause the tool and its shank be withdrawn or slippedout of place to such an extent as to bring the impact end of its shankoutwardly beyond the inner end of the chuck then the hammer 32 will passwithin the coil 4 out of the influence of the coil 3 and will be held bythe coil 4 against a reciprocatory movement, thus obviating thehammering action of the hammer on the in- 'ner end of the chuck.

hat I claim is" 1. An electric hammer comprising a suitable casing, ahammer proper, arranged to reciprocate within the casing,electromagnetcoils for operating the hammer and a demagnetizing-coil forreleasing the hammer.

2. An electric hammer comprising a suitable casing, a tool-holding chuckat one end of the casing, a hammer proper arranged to reciprocate withinthe casing, electromagnetcoils for operating the hammer and ademagnetizing-coil surrounding the position which the shank of the toolis intended to occupy for releasing the hammer from the tool.

3. An electric hammer comprising a suitable casing, a hammer proper,arranged to reciprocate within the casing, electromagnetcoils foroperating the hammer and means for varying the duration of theenergization oi a coil for the advance and return strokes of the hammer.

4. An electric hammer comprising a suitable casing, a hammer properarranged to reciprocate within the casing, electromagnetcoils foroperating the hammer including a coil of higher inductive power near theend oi? the casing where the hammer is intended to strike the tool, acoil of less inductive power farther from said end of the casing and ademagnetizing-coil nearer the said end ofv the casing.

5. The combination with the hammer proper and coils, one at the limit ofits advance and one at the limit of its return stroke for actuating thehammer, of an intermediate coil arranged to act upon the hammer bothduring a part of its advance and during a part of its return stroke andmeans for energizing and deenergizing said intermediate coil at eachstroke of the hammer.

6. The combination with the hammer proper and coils, one at the limit ofits advance and one at the limit of its return stroke for actuating thehammer, of an intermediate coil for acting upon the hammer during a partof its advance and during a part of its return stroke, and ademagnetizing-coil arranged to be energized simultaneously with the saidintermediate coil.

7. The combination with the casing comprising a central brass tube, anexterior steel tube, tool-chuck forming a closure for the tubes at oneend and a handle and cushionsupporting block forming a closure for thetubes at the opposite end, of a series of coils interposed between thetubes, a hammer proper free to reciprocate within the central tube, aspring-actuated circuit maker and breaker under the control of the handof the operator and means for supplying and regulating electric energyto the coils.

8. The combination with the reciprocating hammer and theelectromagnet-coils for operating the hammer, of the central casingwithin which the hammer operates, the said central casing being providedat its tool end with an air-passage opening communication between itsinterior and the outer air.

9. The combination with the reciprocating hammer and the electromagnetsfor operating it, of the casing comprising an inner tube, an outer tube,a chuck and handle, the said chuck being provided with air-passageswhich register with air-passages in the wall of the outer casing andopen communication between the interior of the inner tube and the outerair.

10. The combination with the casing, a hammer arranged to reciprocatewithin the casing and electromagnetic coils for operating the hammer, ofa tool-holding chuck having its inner end in proximity to one coil andso spaced from an adjacent coil as to permit the hammer to remain freefrom the influence of said adjacent coil when in contact with the end ofthe chuck.

In testimony that I claim the foregoing as my invention I have signed myname, in presence of two witnesses, this 8th day of July, 1904.

WILLIAM F. WAGNER.

Vitnesses FREDK. HAYNES, HENRY THIEME.

